return nil
	}

	r.contentHasher = cs.Type.Hasher()
	if r.contentHasher == nil {
		return ErrInvalidChecksum
	}
	return nil
}

// AddServerSideChecksumHasher adds a new hasher for computing the server-side checksum.
func (r *Reader) AddServerSideChecksumHasher(t ChecksumType) {
	h := t.Hasher()
	if h == nil {
		return
	}
	r.ServerSideHasher = h
	r.ServerSideChecksumType = t
}